What is Diabetes Mellitus?

Diabetes Mellitus is a common disease of both cats and dogs. The classification of Diabetes is similar to humans, type 1 and type 2. Cats can have both type 1 and type 2 diabetes, while dogs are almost invariably type 1 diabetics. Type 1 diabetics require insulin for treatment, while type 2 diabetics can sometimes control their disease with diet and weight management. Animals that are more likely to become diabetic if they are overweight or obese, have pancreatitis, are taking certain medications, or have Cushings disease, to name a few. Diabetes, in some cases, is a preventable disease.

Diabetes Mellitus is caused by the bodies inability to produce insulin from the pancreas in specialized cells. Insulin is required for the use of glucose. Glucose is the primary source of energy for the body. All cells in the body require glucose in order to operate properly. When the body no longer has insulin and therefore cannot use glucose as an energy source, the body thinks that it is starving even though there is a lot of glucose in the blood. This tricks the body into looking for alternative energy sources and it starts to produce ketone bodies. The result is Diabetic Ketoacidosis (DKA), where a massive production of ketones leads to a drop in blood pH (acidosis), nausea and vomiting, and severe dehydration. DKA is a medical emergency and treatment requires hospitalization. Fortunately, most diabetics are diagnosed and started on treatment prior to this eventuality.

Diabetes Mellitus causes an increased to ravenous appetite, excessive drinking and urination, weight gain and then loss, neuropathy, and cataracts. Other clinical signs may be present, but are less common.

How do you diagnose pet diabetes?

Diabetes Mellitus is diagnosed through blood work and urinalysis, in combination with clinical signs. Glucose levels in the blood will be elevated and there will also be glucose in the urine. If there is a question about the diagnosis, Diabetes can be confirmed with a Fructosamine level (the equivalent of average glucose levels over about 2 to 3 weeks time), or testing the blood and urine over a period of time and finding persistent elevation of the glucose levels.



Diabetes Mellitus treatment is multifactorial. It is a combination of weight control, insulin, diet, careful monitoring and treatment of any concurrent diseases. Obese animals and animals with other diseases have some degree of insulin resistance, making treatment more difficult. It is important to take the excess weight off and treat concurrent disease. There are special diets made specifically for diabetic animals. These diets work in conjunction with the insulin to maintain normal and regular glucose levels and encourage a healthier weight. Exercise is also an important for weight management.


Diabetes Mellitus management is most successful with a close relationship with your veterinarian, especially when first diagnosed. It can require many months of testing and adjusting to find the best diet, exercise regimen, and insulin dose for your pet. This does require many trips to the hospital. However, for those that are willing and able, at home testing with good communication with your veterinarian can decrease some of those visits.


D. Raenell Killian, DVM
Prescott Animal Hospital